July 11, 2013
New PEM® type SFN™ spinning flare nuts from PennEngineering® are designed to rotate freely when permanently captivated in thin metal sheets for quick attachment to mating hardware and reduced need for loose fasteners such as flange nuts. When they are paired with a self-clinching stud or other fixed, externally threaded hardware, all loose hardware can be eliminated from an application.
The one-piece flanged steel hex nuts install in steel, stainless steel, and aluminum sheets of any hardness and as thin as 0.04 in. Upon installation, the nut becomes permanently captive and will spin freely in the sheet to accommodate mating hardware for final component attachment.
The user inserts the fastener into a properly sized, prepunched, and embossed mounting hole and then applies sufficient squeezing force to flare the shank. When installed, the nut will appear identical to a standard flanged hex nut above the sheet and will remain flush on the other side.